How can a grand jury obtain witness testimony and records?

A grand jury obtains witness testimony and records primarily through the use of a subpoena, a formal legal instrument that commands an individual to appear and provide testimony or produce specific evidence.123

When seeking documents or physical evidence, the grand jury may issue a subpoena duces tecum, which requires the recipient to deliver the requested papers or records. Regarding witness testimony, the grand jury’s power is similar to that of a trial court; witnesses are generally required to appear and testify. If a witness refuses to comply, they may face charges of contempt, though they cannot be compelled to provide testimony that would incriminate themselves.213

While prosecutors often facilitate these investigations by presenting evidence and questioning witnesses, the grand jury maintains the authority to conduct its own investigations to determine if there is probable cause to issue an indictment. These proceedings are typically conducted in secret to protect the integrity of the investigation and the reputations of those involved.43